Switch mechanism



March 3, 1931. w H sc 1,794,924

SWITCH MECHANISM Filed May 27. 1929 Fly 1.

F/yZ. 7 9/5 52a 23 Z7 "8 l6 l5 /a /7 23 2.9

III/[IIIIII/IIIIIIIIIIIIII'IIIIIIIIJ INVENTOR Wa/fer H Sc/rmmz ATTORNEYPatented Mar. 3, 1931 UNITED STATES PATENT OFFICE WALTER H. SCHRAMM, OFPITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC 8cMANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA SWITCH MECHANISMApplication filed May 27, 1929. Serial No. 366,345.

My invention relates to switch mechanism and particularly'to switchesfor controlling current used in street cars and the like.

' An object of my invention is to provide a switch that is capable ofuse in circuits carrying heavy current values and is relatively compactin construction in order that it may be used in installations wherespace limitations preclude the use of switches of large dimensions.

A further object of my invention is to provide a switch, having theabove-noted characteristics, wherein the parts thereof may principallybe stamped from sheet metal and assembled with. a minimum of effort.

A further object of my invention is to provide a switch wherein theswitch arm is part of a toggle assembly and wherein the contact thereofslides over the fixed contact during opening movement thereof, therebyrendering the contacts self-cleaning.

A further object of my invention is to provide a switch that may readilybe assembled between thepole pieces of a blowout magnet of substantiallystandard construction.

A further object of my invention is to provide a switch wherein theswitch mechanism is mounted between pole pieces of a blowout magnet andwherein the fixed contact is mounted upon an insulating support oiU-shape that is spaced from the pole pieces I to constitute a support.for the switch mechanism, and attached thereto adjacent to theextremities of the support, whereby the creepage distance between thecontact and the pole pieces of the magnet is substantially increased.

These and other objects that will be made apparent throughout thefurther description of my invention are obtained by means of the switchapparatus hereinafter described and illustrated in the accompanyingdrawings, wherein,

Figure 1 is a longitudinal section through switch apparatus embodyingfeatures of my invention, taken 011 the line 1 1 of Fig. 2.

Fig. 2 is a plan view of the switch device shown in Fig. 1.

Fig. 3 is a longitudinal sectional view SlIIli':

lar to that shown in Fig. 1 but withthe switch parts shown in'openposition.

Referring to the drawings, the switch de vice comprises a metalsupporting structure 4 of U-shape in cross section that serves as a baseor support for the switch apparatus to be-hereinafter described, and ablowout coil 5 and pole pieces 6, which are of the usual constructionand which extend longitudinah ly of the support between the side walls 7thereof, as indicated in Figs. 1 and 2. Insulating plates are disposedadjacent to the inner sides of the pole pieces to form an arc chute 9 inwhich the are, incident to the opening of the switch contacts, is drawnand from which it is moved, under the influence of a magnetic field,between the pole pieces of the electromagnet coil 5.

The fixed contact of the switch device comprises a metal plate 11 thatis mounted upon the bottom of an insulating support 12 of U- shape, theintegral sides 13 of which are spaced from the side plates 7 byinsulating washers 14, theside plates of the insulating support beingattached to the side plates 7 of the main support bymeans of rivets 15.By reason of this construction, a maximum creepage distance is provided,within the space limitations of the device, between the contact plate 11and the side plates 7 of the main support, which, as will be shownlater, are conductively connected to the switch arm. The contact plate11 is connected to one terminal 16 of the blowout coil.

The switch arm comprises a pair of toggle links 17 and 18, the formerbeing provided, at its free end, with a contact member 19 that isdisposed between a pair of plates constituting the free link 17, thecontact member 19 being cylindrical in form and so mounted andfrictionally clamped between the plates of the link 17 that it may beturned, when desired, to bring a different portion-thereof intoengagement with the contact plate 11. The link 18 comprises two spacedplates that are pivotally mounted upon a shaft 21 and positioned bymeans of spacing sleeves 22, as indicated in Fig. 2. The links 17 and 18are connected by knee pivot bolts 23 or may be pivotally connected byrivets, as desired.

' Arms 24 of the plates of the pivotal link 18 extend beyond the sideplates 7 and their outer ends are connected by a bolt 26 and a sleeve toconstitute an operating handle for the switch. Movement of the operatingarms 24 is limited by stops 27 and 28 that are bent'inwardly from theedges of the plate 7 of the support, and the stop '28 serves also as astop for arresting opening movement of the free link 17.

A tension spring 29 is connected, at one end, to the pivot shaft 21 ofthe pivotal link 18 and, at its other .end, to a pin 31 that isconnected to the free end of the link 17, as

indicated in Figs. 1 and 2. The spring 29 normally tends to fold orcollapse the toggle links 17 and 18 and causes the angular position ofthe link 17 to be reversed with respect to the link 18 when the kneepivot 23 of the toggle is moved past a center line connect-ing the pivotshaft 21 and the shaft 31.

As shown in Fig. 1, the switch parts are in the closed position whereinthe arms 24 are yieldingly pressed against the stop 27, and the contact19 is yieldingly engaging the fixed contact plate 11. When it is desiredto open the switch, the operating arms 24 are turned counter-clockwise,thus moving the knee pivot 23 past the center line referred to above.When this occurs, the spring 29 contracts and causes a reversal of thepositon of the free link 17 to the open position, wherein it will beseen that the opening movement of the link 17 is arrested by the stop28, which also serves to limit the movement of the operating handle. Thespring 29 retains the parts in the open position shown in Fig. 3 untilthe operating handle has been returned to its original position, whereinthe contact member 19 is in engagement with the fixed contact- 11. i

Referring to Fig. 1, it will be noted that, when the operating .arms 24are moved in a counterclockwise d rection, the links 17 and 18 are movedto a straightened position, thus causing sliding movement of the contact19 from the full-line closed position to the line indicated in brokenlines in Fig. 1, before the link 17 is actually moved to itscircuit-opening position. This sliding or Wiping action, during eachopening operation, tends to clean the contact, audit will be notedthatthe contact 19, at the moment of actual separation from the contact 11,is a considerable distance from the original point of contact.

7 Thus, any arcs that are drawn upon separation of the contacts do notburn the portion of the contact normally in engagement with the contactmember 19 while the switch is in closed position. Since the contact 19may be rotated to bring a new surface into engagement with the contactplate 11 when the switch is in closed position, clean, smooth contactsurfaces may be maintained in 'engagement.

From the foregoing, it is apparent that a compact, ruggedand effectiveswitch is provided, capable of use in inductive circuits havingrelatively high current values, such as in railway service and whereonly one side of the circuit is opened and that the switch isinexpensive to manufacture .and may be disposed in places where spacelimitations are an important factor.

While I have illustrated but one embodiment of my invention, it willbeapparent to those skilled in the art that various changes,modifications, substitutions, additions and omissions may be made in theapparatus illustrated, without departing from the spirit and scope of myinvention as set forth in the appended claims.

1 claim as my invention:

1. A switch comprising a support having a pair of side members, a switcharm conductively connected to the support, a contact member betweentheside members adapted to be engaged by the side members and an insulatingsupport of U-shape for supporting the contact member, the side plates ofthe insulating support being spaced from the side members and connectedthereto adjacent the extremities of the plates to provide maximumcreepage distance between the contact and the side members of thesupport.

2. A switch comprising a U-shaped support, a switch arm pivoted betweenthe side members of said U-shaped support and conductively connectedthereto, an insulating member of U-shape having a contact member in thebottom thereof, said insulating member being in contact with saidU-shaped support only at points spaced from said contact member toprovide maximum creepage distance between the contact and the support.

3. A switch comprising a U-shaped support, a pair of pivotally connectedtoggle side members of the U-shaped support and provided with anoperating handle extend-- ing without the U-shaped support, the other ofsaid toggle links carrying a contact member, an insulating supportcarrying a stationary contact and secured to the U'shaped support onlyat points at a distance from said stationary contact.

4. A switch comprising a supporting member having parallel walls,'afixed contact and a movable contact, said fixed contact being mountedbetween said walls by an insulating member spaced from said walls andsecured thereto only at a point ata distance from the fixed contact toprovide maximum creepage distance between the contact and the support.

In testimony whereof. I have hereunto subscribed my name this 20th dayof May, 1929.

' WALTER H. SCI-IRAMM.

